1. Field of the Invention
The present invention relates to a cogeneration vehicle system utilizing a fuel cell car, and to a mobile unit which constitutes a component of the system. More particularly, the present invention relates to a cogeneration vehicle system and a mobile unit which permit water and heat, generated at the time of power generation in a fuel cell car, to be effectively utilized in a mobile unit (e.g., a trailer) which is jointed to the fuel cell car, or in an immobile facility (e.g., a residential house) by way of such a mobile unit.
2. Description of the Background Art
In recent years, fuel cell-based power generators have been attracting attention since such power generators have a high energy efficiency and yet are environmentally friendly. Power generation by a fuel cell occurs through a reaction which is a reversal of electrolysis of water, where hydrogen and oxygen are reacted to generate power. Therefore, the resulting by-products from power generation by a fuel cell are water and heat. No harmful gases, such as nitrogen oxides, are emitted as a result of power generation by a fuel cell (note that extremely small amounts of harmful gases may be emitted from some types of fuel cells).
Various types of fuel cells have been developed and studied. Among others, a fuel cell in solid polymer form has a higher energy efficiency than that of other types of fuel cells, and produces little carbon dioxide gas, resulting in less unfavorable impact on the environment. Moreover, a fuel cell of solid polymer form can operate at a lower temperature (about 70° C.) than other types of fuel cells, thereby allowing for an easy adjustment of the amount of generated power.
Therefore, there are expectations for utilizing fuel cells of solid polymer form as alternative sources of motive power in automobiles (to replace conventional internal combustion engines), or as cogeneration energy sources to be used in dwelling or accommodation facilities (e.g., residential houses or trailer houses).
However, in the case where fuel cells are to be used as a source of motive power for an electromobile and as a cogeneration system in a residential house or the like, a power generator incorporating a fuel cell must be installed at each of the electromobile and the residential house or the like, thereby resulting in a high installation cost. Moreover, while it may be possible in the residential house or the like to effectively utilize substantially all of the water and heat which are produced through power generation by the fuel cell, the electromobile will only use the generated electric power and discard the generated water and heat, so that optimum use of energy is not attained in the electromobile.
Accordingly, techniques for utilizing the water and heat generated by a fuel cell power generator mounted in an electromobile for indoor/outdoor cogeneration purposes have been proposed in Japanese Patent Laid-Open Publication No. 8-273680, for example. In this conventional technique, an electromobile having a fuel cell power generator mounted therein is connected to a housing or a tent, so as to allow the electric power, water, and heat which are produced through the fuel cell power generation in the electromobile to be supplied to the housing or tent.
However, the conventional technique utilizes the electromobile incorporating the fuel cell power generator as an immobile power generator (i.e., a power generator which is fixed in place). Therefore, the inherent travelling capabilities of the automobile cannot be exerted during power generation. On the other hand, cogeneration can no longer be realized once the automobile is disconnected from the housing or tent in order to allow the automobile to travel.
Thus, the conventional technique has problems which are difficult to reconcile.